Linagliptin: uses, side effects and cautions

Linagliptin belongs to the DPP-4 inhibitor group of type 2 diabetes medicines. The emc information says it blocks dipeptidyl peptidase 4, the enzyme that breaks down incretin hormones, which leads to a sustained increase and prolonged action of active incretins. The result is more insulin released when blood sugar is raised and less glucagon released. The NHS summarises this as increasing the amount of insulin the body produces and lowering blood sugar.

It is licensed with diet and exercise, on its own when metformin is unsuitable because of intolerance or kidney problems, and with other diabetes medicines including insulin. The product was previously sold as Trajenta, according to the emc listing.

The tablet is taken once a day, swallowed whole with a glass of water without crushing or chewing, with or without food. The NHS says to continue long term unless your doctor advises otherwise. If a dose is missed, take it when you remember unless the next is close, in which case skip it.

One practical distinction from sitagliptin is that the SmPC requires no change in the 5 mg dose for reduced kidney or liver function or older age. When it is combined with a sulfonylurea or insulin, those partner medicines may be reduced to avoid hypoglycaemia.

The NHS lists common effects as cold-like symptoms with a blocked nose, cough and constipation, and hypoglycaemia when taken alongside other diabetes medicines. The SmPC lists uncommon nasopharyngitis, hypersensitivity, rash and cough, and rare pancreatitis, angioedema, urticaria and bullous pemphigoid. Raised blood lipase is common but does not by itself mean pancreatitis.

The NHS tells you to call 999 if you think you might be having anaphylaxis, pancreatitis or a serious skin reaction. Sudden severe stomach pain, blistering skin or swelling of the face and throat fall into that category.

It should not be used if you have been allergic to linagliptin, per the NHS, which also lists pancreatic conditions as a reason it may not be suitable. The SmPC says it is not for type 1 diabetes or diabetic ketoacidosis, and that caution applies to people with a history of pancreatitis.

The NHS names carbamazepine (an epilepsy medicine), rifampicin antibiotics and other diabetes medicines as possible interactions. The SmPC explains that rifampicin lowers linagliptin levels by roughly two fifths, which may reduce its effect, and that ritonavir raises exposure two to three times, which is considered manageable. No clinically significant interaction was found with metformin, sulfonylureas, digoxin, warfarin, simvastatin or oral contraceptives.

The NHS says linagliptin is not used in pregnancy or breastfeeding. The SmPC phrases it as preferable to avoid in pregnancy and leaves a decision between stopping breastfeeding or the medicine. Alcohol affects blood sugar, so the NHS advises avoiding it. Driving is not usually affected unless you have low blood sugar symptoms.

Linagliptin is prescription only. If you suspect it has caused a side effect, you can report it via the Yellow Card scheme.